Method of forming interchangeable sign letters



Dec. 25, 1923. 11, 78, W. L. CLARK METHOD OF-FORMING INTERCHANGEABLE SIGN LETTERS Filed Feb. 27 1922 Patented Dec. 25, I923.

WARREN L. CLARK, OF NEW YORK, N. Y.

that

7 METHOD or FORMING INTERCHANGEABLE SIGN rn rrnns,

Application filed. February 27, 1922. Serial No. 539,593.

, York city, State of New York, have inventthe bases of the letters.

ed a certain new and useful Improvement in Methods of Forming Interchangeable Sign Letters, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying draw ings, forming part of this application, in which My invention relates to interchangeable letter signs and consists in an improved method of forming the letter tabs to be used in such signs and in the improved product of such method.

The object of my invention is to produce a letter tab having a hooked upper edge by which the letter may be suspended and in which the letter will be accurately located so that adjacent letters on'a signboar'd to which the tabs are applied will align with each other.

In the accompanying drawings Figures 1 and 2 illustrate stages in an old method of preparing such letter tabs.

Figures 3 and 4 illustrate stages in my improved method of -manufacturing the tabs, the completed tab produced by each method being shown approximately in'Figure 5, although it will be understood from this specification that the tabs produced by my improved method are uniformly accurate to an extent hitherto unobtainable.

In both of these methods it is customary to lithograph a large number of letters on a single sheet 1 of metal which is then enameled and baked. It may be assumed that this lithographing operation locates the letters accurately so that exact shearing of the individual tabs from the plate and the accurate forming of their hooked edges will produce letters uniformly positioned in their respective tabs. In the old method illustrated in Figurescl and 2, these tabs are formed by cutting the sheet 1 along the vertical lines 2 which are perpendicular to Each strip so formed is then inserted in a press-the first ope-ration of which would be to shear the first tab from the strip by making a horizontal cut 5 and then form the hooked portion 4 by a suitable die operation. In this operation, the strip would be fed longitudinally against a stop positioned so as to engage the upper end of a strip. lmpossible to set the stop exactly so that the tab will be precisely the right length and ,a

minute departure from an exact setting of the stop while unnoticeable in the first few tabs produced would be readily apparent in the tabs cut from the lower portion of the strip as the length of these strips may include twenty-five or more tabs and the error in the stop setting becomes cumulative as successive tabs are cut from the'strip.

. An additional source of error arises from the fact that the thin rolled metal forming the plates possesses slight bends, creases or other inequalities in its surface which are increased in number during the successive shearing operations and the effect of which inequalities in the first tab is to vary the length of the tab and therefore the exactness of the lower edge of that tab and of the upper edge of the next tab blank 8 and the inequalities of the surface in the second tab will similarly affect the third tab blank in addition to the error produced by the first tab.

Briefly, by the old method each tab hook will be formed after the blank is severed from the strip and its location relative to the letter 011 the tab will be dependent upon the upper edge of the blank. With my improved method I provide the sheet 7 in the same manner as has been done previously but instead of shearing the letters successively from vertical strips and separately forming a hooked portion for each tab after the blank is cut, I form my strips, by cutting along lines 8, Figure 3, in which a plurality of letters appear in a horizontal line and this strip is then provided with a continuous hooked upper edge 9 after which the individual tabs are separated by respective vertical cuts 10. The number of tabs in each horizontal strip may be as high as fifty without exceeding the total strip dimension of about half as many letters in a vertical strip. This is due to the fact that the width of many letters and characters is much less than their height.

While Figure 3 shows the letters of each strip as being duplicated and therefore of equal width. this is immaterial as letters of different widths may follow each other on each strip.

Whether or not these individual vertical cuts 10 are accurate is immaterial as depar- Now it is practically tures of cuts 10 from the normal will not affect the positioning ofthe letter relatively to the hook, which positioning determines the alignment of the letters in a sign.

It will be understood that each horizontal strip is fed against a stop which engages its top edge similarly to the stop previously referred to as being used for the vertical strips. Any variation in the setting of this stop will only affect the one strip as the gaugernay be reset for each strip without unduly increasing the time of producing a given number of tabs while a repeated setting of the stop in the old method tovsecure thesanie result would require an individual setting for each tab.

With the old method referred to, it is necessary to provide a separate forining die for each size of tab whilewith my method it is the strip as a whole which 'is-be-nt and only one bendingdie is required, the severance of the tabs from the strip being formed by a press whichoperates independently of the width of the latter.

What I claim is i 1. 1 An improved method of forming interchangeable sign letters'consisting in severing'a row of-letters from a blank, thus pro ducing a strip, then'it'olding one edge of said Btrip andfinally dividing the strip including its folded edge transversely.

2. An improved method of forming intertransversely so as; to locate the letters or characters centrally in their. fields. 7 p v In testimony whereof I hereunto afiix my signature this 14L day of February, 1922, WARREN L., CLARK.

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